The present invention relates to a method of operating an air conditioner of the type using refrigerant and having a plurality of evaporator fan units located in individual rooms requiring air conditioning (indoor units) connected to a common compressor-condenser unit (outdoor unit) for receiving refrigerant therefrom, such that a desired number of indoor units are operated at a time.
In the field of air conditioning, it is desired to operate as many indoor units as possible with a common outdoor unit at a time. However, the number of indoor units connected to a single outdoor unit is limited since the outputs of respective indoor units are reduced to provide unfavorable air conditioning in case the sum of outputs of all the indoor units is beyond the capability of the outdoor unit. Therefore, for increasing the number of the indoor units, it has been necessary to correspondingly increase the capacity of the outdoor unit, resulting in a raised cost of the air conditioning system as a whole.
In case the sum of outputs of indoor units is equal to the output of a single outdoor unit and the indoor units are increased in number, respective lengths of refrigerant pipes between the common outdoor unit and respective indoor units are varied depending on the room arrangement in a house. In other words, the ratio of the length of the shortest refrigerant pipe to that of the longest refrigerant pipes is greatly varied as the number of the indoor units is increased. When all the indoor units are operated at a time, the indoor unit remote from the outboard machine, i.e. the indoor unit connected to the outdoor unit through comparatively long refrigerant pipes can share only a small part of the refrigerant, and cannot fully exert the cooling power.
To avoid this problem, in conventional air conditioners of the kind described, various measures are taken in an effort to make respective lengths of the refrigerant pipes substantially constant.